1) Field of the Invention
This invention relates generally to improved joints for connecting water supply pipe together and, in particular, to a pipe joint which is used to join together pipes of same sizes and materials, and which utilizes compression seals between the pipes and the joint.
2) Description of the Prior Art
As shown in FIGS. 11-13, in a prior art pipe joint, a seal ring 2 that is provided on inside of a joint half housing 3, 3 seals between the ends of separated pipe 1, 1, an inner rims 5, 5 of the joint half housing 3, 3 is being engaged into a groove 6, 6 formed at each end surfaces of separated pipe 1, 1.
The joint half housing 3, 3 is becoming on unity of housing to combine each others by the tightening of the bolts and nuts 4, 4.
As shown in FIG. 13B, the seal ring 2 is generally C-shaped in cross section and formed of a rubber, and has a flexible lip portion 2a at each end thereof, each of which is embedded and sealed within the outside surfaces of both ends of separated pipes 1, 1.
As shown in FIGS. 13A and 13B, the seal ring 2 has an inside diameter which is less dimension than an outside diameter of separated pipe 1, 1 to keep close tightly for a fluid leakage in the pipe joint.
Notwithstanding, disadvantage of prior art pipe joint is the inability easily inserting of the seal ring on the outside surface of both ends of separated pipes.
If during the fitting of the pipe joint to separated pipes, each joint half housing to be removed by removing of the bolts and nuts before the seal ring being to engage on both end of separated pipes; since a bolts and nuts is used for combination of the joint half housing, a lost bolts and nuts is caused by a poor working conditions at limited work spaces, this encounters unnecessary expense.
A correct placing and alignment of the inner rims of the joint half housing into the groove at both end surfaces of separated pipes is required for connecting the separated pipe together.
This is particulary a problem that the joint does not have itself the ability to recognize a correct alignment of the joint with separated pipes, that results in lowered reliability.
If during the fitting of the pipe joint to separated pipes, the seal ring may be embedded and sealed on outside surfaces of both ends of separated pipes, which fluid passing through the pipe joint is sealed without operator awareness, because an inside diameter of the seal ring is smaller dimension than the outside diameter of separated pipe 1, 1. However, this could cause the fluid leakage between the seal ring and the ends of separated pipe under normal water working pressure condition because of its lack of compression force of the seal ring within the joint housing.
Another form of prior art pipe joint is described in Japanese Patent Publication No. 55-25316 of 1980.
According to this apparatus, differing from that using the conventional pipe joint type, portion of the seal gasket having grip members in the joint housing, and which is particularly suited for use in connecting together pipes to more securely grip at each end smooth surfaces of separated pipe.